1. Technical Field
The disclosure relates to a receiver device, and more particularly to a device and a method for calibrating a receiver equalizer.
2. Related Art
FIG. 1 is architecture of an ordinary communication system, which includes a transmitter 101, a channel 102 and a receiver equalizer 103. The receiver equalizer 103 includes an adaptive filter 110, a Clock Data Recovery (CDR) unit 120 and an adaptive controller 130. Here, it should be noted that persons of ordinary skill in the art shall understand that the operation of the above elements belongs to the prior art, and for brevity, detailed operations of the elements will not be described here.
The receiver equalizer 103 in the prior art adjusts a filter control signal G of the adaptive filter 110 by determining whether channel attenuation is over-compensated (over EQ), or under-compensated (under EQ), during data transition, and compensates a channel signal VR according to the filter control signal G. In practice, several problems may be encountered in the prior art.
1. When the input channel signal of the receiver equalizer 103 is 01010101, 001100110011, 000111000111, 0000111100001111 or 00000111110000011111 etc, that is, the binary sequence contains successive low-order binary bits (low-order representing 0), and successive high-order binary bits (high-order representing 1), and the number of the low-order binary bits is equal to that of the high-order binary bits, the data has desirable distinguishability, and it is better not to adjust the filter control signal G. However, in the case of repeated transition of data of the same length, the prior art still continuously adjusts the filter control signal G. In this way, in the case of repeated transition of data of the same length, when channel attenuation is over-compensated a more serious over EQ phenomenon may occur to a compensative signal X if the adaptive filter 110 is adjusted repeatedly; conversely, when channel attenuation is under-compensated, a serious under EQ phenomenon may occur to the compensative signal X if the adaptive filter 110 is adjusted repeatedly.
2. When the compensative signal X obtained by the adaptive filter 110 compensating the channel signal VR is under-compensated, the filter control signal G of the adaptive filter 110 must be quickly adjusted to enhance the compensation for the channel signal VR. When the compensative signal X obtained by the adaptive filter 110 compensating the channel signal VR is over-compensated, the filter control signal G of the adaptive filter 110 must be adjusted quickly to reduce the compensation for the channel signal VR. The prior art can only gradually adjust the compensation effect, but cannot quickly and properly adjust the filter compensation effect of the receiver equalizer, resulting in reduced system efficiency.